Emergent Phenomena in Ferroelectric/van der Waals Heterostructures

Professor Xia Hong; Department of Physics and Astronomy, University of Nebraska-Lincoln

The heterointerfaces between ferroelectrics and two-dimensional (2D) van der Waals materials present a versatile platform for achieving novel interfacial coupling, nonvolatile field effect control, and nanoscale programmable functionalities. In this talk, I will discuss a range of emergent phenomena in ferroelectric/vdW heterostructures mediated by interfacial coupling of charge, lattice, and polar symmetry. By combining polarization doping with nanoscale domain patterning in a ferroelectric gate, we have mapped out the transport anisotropy in monolayer to 4-layer 1T’-ReS2 [1] and created one-dimensional graphene superlattice in the high Kronig-Penney potential limit [2]. The interface-epitaxy with ReS2 leads to scalable formation of ferroelectric polymer P(VDF-TrFE) thin films composed of highly ordered, close-packed, 10 and 35 nm wide crystalline nanowires [3]. We observe enhanced polar alignment, piezoelectricity, and Curie temperature in thin CuInP2S6 flakes prepared on ferroelectric oxide PbZr0.2Ti0.8O3 (PZT), which can be attributed to the interfacial strain imposed by PZT [4]. An unconventional tuning effect of second harmonic generation signal is enabled by the polar coupling of 1L MoS2 with either the polar domain or the chiral dipole rotation at the domain wall surface in PZT thin films and free-standing membranes [5]. Our study showcases the rich research opportunities offered by integrating ferroelectrics with 2D materials.
[1]     D. Li et al., Phys. Rev. Lett. 127,136803 (2021).
[2]    T. Li et al., Phys. Rev. Lett. 132, 056204 (2024)
[3] D. Li et al., Adv. Mater. 33, 2100214 (2021).
[4]     K. Wang et al., ACS Nano 17, 15787 (2023). 
[5]    D. Li et al., Nat. Commun. 11, 1422 (2020); D. Li et al., Adv. Mater. 35, 2208825 (2023).